TGFB1 and Paroxysmal atrial fibrillation: A recent study showed that serum levels of TGF-β1 gradually increased in the following four groups: control group, hypertensive patients, paroxysmal AF secondary to hypertension, and chronic AF secondary to hypertension, thereby demonstrating that TGF-β1 may contribute to the initiation and sustainment of AF in hypertensive patients via atrial remodeling and fibrosis (Lin et al., 2015).